//
//  UIBarButtonItem+Extension.swift
//  727-黑马08微博-测试
//
//  Created by apple on 15/8/9.
//  Copyright © 2015年 itheima. All rights reserved.
//

import UIKit

extension UIBarButtonItem {
    convenience init(imageName: String, target: AnyObject?, action: String?) {
        let button = UIButton()
        button.setImage(UIImage(named: imageName), forState: UIControlState.Normal)
        button.setImage(UIImage(named: imageName + "_highlighted"), forState: UIControlState.Highlighted)
        button.sizeToFit()
//        设置监听方法，判断action是否存在
        if let actionName = action {
        
            button.addTarget(target, action: Selector(actionName), forControlEvents: UIControlEvents.TouchUpInside)
        }
//        调用指定的构造函数
        self.init(customView:button)
        
    }
}
